Process of producing dried milk.



PATENTED MAY 19, 1908.

J. A. JUST.

PROCESS OF PRODUCING DRIED MILK.

APPLICATION FILED NOV. 24, 1906.

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FFICE.

JOHN A. JUST, OF SYRACUSE, NEW YORK.

PROCESS OF PRODUCING DRIED Specification of Letters Patent..

Patented May 19, 1908'.

Application filed November 24, 1906. Serial No. 344,897.

To all whom it may concern:

Be it known that I, JOHN A. J UST; a citizen of the United States, and resident of Syracuse, New York, have invented certain new and useful Im rovements 1n Processes of Producin Drie Milk, of which the following is a specification, accompanied by drawings.

This invention relates to animproved process of evaporating fluids or liquids carrying dissolved solids, as for instance milk or milk like substances, to form dried products, and the object of the invention is to obtam'a dry product from suchliquids of better quality than heretofore produced, and enable a is greater quantity of material to be dried in a after fully described and claimed in this s ecification, certain typical arrangements apparatus suitable in carrying out said process eing illustrated .b means of the accompanying drawing, w iich is a longitudinal elevation of the apparatus partly in section.

, Referring to the drawings, A represents the walls of a chamber, the top B and the bottom of which are broken away in their length. Since this chamber may be thirty or forty feet st uare, the size of the chamber in practice is t erefore very much larger in proportion to the remainder of the apparatus than as illustrated. The bottom t is preferably raised or projected inwardly in the form of a truncated cone having the sides D and top E so that the sides D of the cone and the walls A of the chamber form a chute or collecting space for the dry material.

The chamber which will be designated F is uovided with a jacket G for steam or other heating fluid, and is also provided with the suction pipes lil communicating with the chamber through-the top B. Over the openings of the pipes H are provided tine screens i to aid in preventing dried material from being carried off by thesuction. front of each screen I are piaced revolving biades J adapted to be rotated by motors of suit able character carried by the brackets it: and connected to the blades 5. The revolving blades 3 prevent the dried material, which .cated in dotted lines. communicating with the hollow interior of may be in the form of a powder, from passing off through the suction pi as H.

Within the vacuum 0 lamber F are arranged revolving plates L and 0 adapted to be revolved together in the same direction at a high speed, which may be from two thou sand to eighteen thousand revolutions per minute. These disks may be of steel and are adjustably mounted on the shaft P by any suitable means, as for instance the set screws Q, whereby the distance between the inner surfaces of the plates may be adjusted as desired and normally the surfaces of the disks should almost touch. The shaft P extends upwardly to the collar R and the upper portion of the shaft is hollow as partly indi- A fine aperture S,

the shaft, is provided between the inner surfaces of the plates L and U to permit the liquid material passing down through the inside of the shaft to pass out between the plates.

The collar or hearing it is carried by the stationary hollow shaft T, suitably supported from the top B of the chamber F and ro vided with a funnel U. The revolving sliaft F is carried in a suitable bearing V in the plate E and is adapted to be driven by any suitable form of motor, as for instance the steam turbine W, provided with the intake is. and the exhaust pipe '1, which communicates with the steam jacket G. The jacket is provided with, an outlet a, and as shown,-

extends up around the sides of the vacuum chamber and around the portion of the inner walls D of the chamber. [it the lower portions of the chamber i? are provided the outlets h, communicating with the receiving chambers c, which are of sutiicient'size toreceive a substantially large quantity of the dry material. Above and beiow each receivin chamber c are provided the valves d, provi ed with suitable hand operating devices in the form of cranks c connected to the valve spindies. These valves (i may be of any suitable character preferably one-way vaives, by meansor the arrangement of vaives shown the inateriai may be withdrawn from the va cum chamber F without interfering with normai working conditions of the chambi t hen the upper valves of are opened the lower valves (1 are closed, and before the lower valves are opened, the upper valves should be closed, thereby reventing communication of the chamber g with the outside air. Preferably a hood f is provided ,over the revolving disks L and O to prevent tion of thickness vertically until it becomes so thin that cohesion no longer resists disintegration when the centrifugally severed very fine particles are thrown or discharged radially in a mist-like form, permeating substantially the entire chamber F. In the case of a compound liquid, like milk, the contained droplets of liquid, such as butter fat, are'likewise co-extended radially in the same manner as the carrying or emulsifying liquid, and each similarly breaks up into a myriad of smaller particles, each particle however, in the case of milk, bein surrounded by a jacketing coat of whey, li e the original droplet. Substantially as complete a vacuum as possible should be maintained in thechamber F and the heat of the chamber should be varied in accordance with the nature of the material being operated upon.

In the described operation, using a pair of horizontal disks, the up er disk is mainl useful to re ulate the thickness of the initia or central, a or of milk or other fluidto be dried since t e liquid no longer touches it when the layer begins to thin out radially. The two disks being plane faced and parallel the s ace between them is of the same ver- 7 tical ei ht at all points While the layer of milk, as on as it persists as a layer, steadil thins out ra ially and cannot occupy the fu 1 vertical space be 0nd a point near the center. It is necessary that this initial, central, fullheight layer of liquid at the center shall be quite thin in order that in thinning down in its radial travel it shall attain a thinness permitting centrifu al disintegration into a mistlike product be 'ore reaching the circumference of the lower disk and for this reason the two disks in practice are set very close together. I

1f liquid milk is bein fed to the revolvin plate L, the milk is discharged by centrifuga force into the chamber F in atomized form and the moisture asses off through the suction pipes H, whe the portion of the milk recovered collects in the lower part of the chamber F in the form of an extremely iine owder, which is received in the chamber V hen the disks L and O are adjusted very close together aimost touching, the milk wil be discharged as a mist of excessive fine dry c.

ness which in its travel through the large chamber F will be reduced to a dry powder, but if it is desired to obtain as a roduct a fluid condensed milk the plates and 0 should be adjusted further apart and revolved at a lower speed, thereby permitting a larger quantity of milk to flow on to the plate L'and issue from between the plates as a coarser mist, in which latter case the milk will collect in the lower part of the chamber F in condensed form, which may be withdrawn into the receiversc. As long as the temperature of the chamber F, the distance apart and the speed of the plates and the quantity of material fed are all maintained substantially constant, a substantially uniform product will be obtained, either as powdered milk or as condensed milk. In either, the roduct is what is known in the milk art as homogenized that is, the milk fat is contained in the form of smaller globules or be lined with tin, or tinned steel or iron,

which may be readily cleansed and sterilized. The chamber is referably constructed with: out corners so t at there will be no opportunity for stale products to lodge in the chamber, and consequently little labor is required to maintain the apparatus in a requisite condition to obtain a product free from extraneous contamination. V

In order to successfully concentrate or reduce liquid. milk to a dry powder, or the so-called condensed form, and in order to obtain a wholesome stable product with all the milk constituents in an'unohanged condition, the full-milk itself or the separated milk and cream added should be treated to homogenize it, that is, treated in such manner as to cause the cream or fatty ortion of the milk to further emulsify wit 1 the albuminous portion and salts, ina much more fine emulsification than exists in ordinary milk. This emulsification is accomplished on the revolving plate in the manner stated and when the product is subjected to desiccation in the apparatus described, a condensed milk or d? product will be obtained, which will he; indefinite time unchanged in a proper package. On redissolving the prodnot with 'the requisite quantity of water fresh milk is formed like that from which the product was made without the use of any preserving agent Whatever. When milk is sprayed in the ordinary manner into a more or less heated atmosphere in order to reduce itto'dryness, the final result is different in many Ways from that obtained in the operation of my apparatus, the state of emulsification being generally made coarser rather the process of desiccation.

than finer as in the process carried out by my apparatus. ()ne serious fault. of the products heretofore obtained by spraying is that the fat quickly becomes rancid and assumes an otherwise disagreeable odor, this being probably due to its existence in a com aratively coarse form in which it is exposet to air;

By atomizing the liquid centrifugally at an extremely high speed as practiced in accordance with my process the dissociation of the various ingredients of the milk is prevented, these ingredients being brought mto most intimate contact and association. ()rdinary spraying, that is, forcing through a contracted orifice of some kind, tends to dissociate the ingredients of the milk the milk fatand-the liquid in which it is suspended having different rates of travel through, and friction upon, the spray nozzle and tending to separate more or less so that some of the albuminous articles may be covered with an excess 0 fat, when such sprayed particles are exposed to a heated atmosphere in Such a product will not keep and becomes rancid uickly, assuming a cheesy order, so that or this reason full cream milk has never been successfully desiccated by the spraying process. 'By atomizing the milk centrifugally in my apparatus, the product is rendered absolutely uniform and is greatly superior, and is produced at much' less cost in a much shorter time than heretofore. Very large uantities of milk can thus be condensed or re uced to a dry powder in a short time. The condensation or reduction of the milk in my process is instantaneous and no changes occur in the milksolids for all harmful reactions require time. Milk as ordinarily condensed m a vacuum pan requires treatment for many hours, according to the capacity of the pan. Frequently five or more tons of milk are placed in these pans at one time and slowly condensed. In my process the milk is supplied in a'continuous stream, and the completed roduct is continuously removed.

The all milk may be separated in an ordinary separator in order to'first remove the coarser im urities and dirt generally met with in mil and by this 0 eration the cream will also be separated. T 1e milk and cream may then be run through a'suitable'machine to unite and mix the two, the cream being I added in proper proportion to the cleansed and separated milk. This mixed milk is.

then fed into my machine, and is thereby atomized and its constituents brought into intimate contact, infinitely more intimate than existed in the fresh milk. This-intimate contact produces a smooth and wholesome article of condensed milk or dry milk product is mixed with water.

individual article inclosed by a sealing pelliclc of drie milk solubles. 1f the impurities were not first removed they would concentrate as the milk concentrates and would become more objectionable and pronounced in the finished product, but these impurities are chiefly removed with the dirt or heavy dirt particles. The dirt of raw milk consists of porous spongy matter, which is teeming with abacteria, and hence my products are especiall free from anaerobic and harmful germs.

Tlie condensed milk product may be sweetened or condensed unsweetened, as desired. Milk condensed in the ordinary way in a vacuum pan, on standing, or in a store, often cakes more or less and a portion of the product solidifies to a crystalline mass. Milk condensed by my process will not se arate its saline portion from the other ingre cuts. The dry powder obtained by my process is very uniform, owing to the initial uniformity createdin the milk before reducing it to the condensed form or dry powder. The fat globules, which in the original milk are seen under the microsco e as fairly far apart and of va 'ing sizes, will be small and very close to eac other after the first treatment or additional emulsification; that is, in the still liquid roduct thrown out by the rotating disk. his intimate emulsification once secured will yield a condensed milk or milk powder, which when mixed with a requisite amount of water for restoring the product the liquid milk will hold its fat uniformly throughout, unlike other milk products in which the fat will rise to the surface when the The speed with which cream 'will rise is, in a way, ro-

ules, and in myproduct these particles of butter fat are almost infinitely fine.

To recapitulate, my process of reparing a dried milk, in its present PIGfBITBt form, consists in first removing the solid im urities of milk, reuniting the cream and mil if necessary, feeding the milk on the surface of a rapidly rotating diskat a point at or near its center to form a layer, the thickness of this initial layer being'regulated'bv the s acin away of another, vertically adjustab e dis above the first and rotating therewith in the same direction, converting this layer into a thin, centrifugally radiating and traveling film of increasing thinness until it becomes too thin to retain its coherence and disintegrates, and discharging the mist-like prodnot formed into a heated and evacuated chamber; the speed of travel of thedisks, I

powder, all the butter fat being reduced to a that the fineness of the mist particles will be state of almost infinite subdivision with each sufficient to insure their complete desiccafilm increasing in thinness outwardly until it film, said film increasing in thinness outand receiving the mistlike product in a %&

tion rior to settling to the bottom of the cham er.

I claim and desire to obtain by Letters Patent the following 1. In the desiccation of liquids, the process which consists in producing a continu ously fed layer of a liquid carrying solids at the center of a rapidly rotating disk, converting the layer into a thin outwardly traveling film, said film increasing in thinness outwardly untilit disintegrates radially into a mistli e form, and receiving the mistlike products in a heated chamber maintained under less than atmos heric pressure, the thickness of the initial a er'and the speed I of the disk being so corre ated Withthe size and evaporative conditions of such chamber that the mist will be fine enough to permit complete desiccationof its particles to a fine powder prior to their settling to the bottom of such chamber.

2. in the desiccation of milk, the process which consists in reducing a thin continuously fed layer 0 milk at the center of a rapidly rotating disk, converting the layer into a thin outwardly traveling film, said film increasing in thinness outwardly until it disintegrates radially into a mistlike form,

heated chamber, the thickness of the initial layer and the speed of the disk being Socorre ated with the size and evaporative conditions of such chamber that the mist will be fine enough to permit complete desiccation of its particles to a fine powder prior to their settling to the bottom of such chamber.

3. In the desiccation of milk, the process which consists in producing a thin continuously fed layer of milk at the center of a rapidly rotating disk, converting the layer into a thin outwardly traveling film, said disintegrates radially into a mistlike form, and receiving the mistlike roduct in a heated chamber maintained on er less than atmospheric pressure; the thickness of the initial layer and the speed of the disk being so correlated with the size and evaporative conditions of the chamber that the mist will be fine enough to permit complete desiccation of its particles prior to their settling to the bottom of such chamber.

4 In the desiccationof milk, the process which consists in removing solid impurities from raw milk, producing a thin continuously fed layer ofthe purified milk at the centeroi a rapidly rotating disk converting the' layer into a thin outwardly traveling Hardly until it disintegrates radially into a mistli e form, and receiving the mistlike product in a heated chamber, the thickness 1 seams orative conditions of such chamber that t mist will be fine enough to permit complete 1 desiccation of its particles to a fine powder prior to their settling to the bottom of such chamber.

5. In the desiccation of milk,-the process which consists in removing solid impurities from raw milk, producing a thin continuously fed layer of the purified milk at the center of a rapidly rotating disk, converting the layer into a thin outwardly traveling film, said film increasing in thinness outward] until it disintegrates radially into a mistli e form, and receiving the mistlike product in a heated chamber maintained underless than atmospheric pressure; the thickness of the initial layer and the speed of the disk being so correlated with the size and evaporative conditions of such chamberthat the mist will be fine enough to permit complete desiccation of its particles to a line powder prior to their settling to'the bottom.

6. In the desiccation of milk, the process .which consists in accelerating the speed of travel of a stream of milk while laterally extending the same until such stream forms a thin layer, continuing the acceleration and extension until the thin layer forms a film of increasing thinness and finally disintegrates into a mistlike form, dischargingthis mistlike product into a chamber of such size and maintained under such cvaporativeconditions that the mistlike articles may completely desiccate into a e powder prior to reaching its bottom, and removing the particles in a dry state.

7. in the desiccation of milk, the process which consists in centrifugally ace lerating the speed of travel of a stream of milk while iaterally extending the same until such stream forms a thin la er, continuing the acceleration and latera extension till the thin layer terms a film of increasing thinness and finally disintegrates into a mistlike torm, discharging this mistlike product into a chamber of such size and maintained under such evaporative conditions that the mistiike particles may completely desiccate into a fine powder prior to reaching its bottom, and removing the particles in a dry state.

8. In the desiccation of milk, the process which consists in spreading out a continuously flowing stream of milk into a thin layer of predetermined thickness and causing such layer to rotate rapidly until centrifugal action causes it first to form a film of increasing thinness" and finally to disintegrate circumconditions that the mistlike product may of the initial layer and the speed of the disk i completely desiccate into a dry fine powder prior to reaching its bottom, and removing the dry powder.

9. In the desiccation of milk, the process which consists in deliverinsl'milk continu- 5 ouslyat the center of a rapi rotating support and by the action of suc support convetting the milk into a rotating, continu-'- ously fio layer, maintaining the continuity of sai layer as such un centrifugal 10 action thins it to a point where surface tension and cohesion no longer sufiice to hold it ether and it circumferenti y into a mistlike form, the

mis'tlike product into a chamber of such size and maintained under such evaporative con- 1 dit ions that the mistlike product may completely desiccate into a dry fine powder prior to reaching its bottom, and removing the dry powder.

In testimony'whereof ,I have signed this 20 specification in the presence of two subscribing witnesses.

JOHN A. JUST.

Witnesses:

OLIN' A; FOSTER, A. L. OBnmn. 

